Time-Dependent Properties of 3D-Printed UHPC with Silica Sand, Copper Slag, and Fibers (2025-04)¶

10.1016/j.istruc.2025.108819

Ravichandran Darssni, Prem Prabhat, Giridhar Greeshma, Bhaskara Gollapalli, Maheswaran Srinivasan
Journal Article - Structures, Vol. 75, No. 108819

Abstract

This study investigates the development and characterization of 3D-printable Ultra-High-Performance Concrete (3DP-UHPC) by optimizing its rheological and mechanical properties. The research examines the influence of fine aggregate gradation, incorporating silica sand (SS-GI: 2–1 mm, SS-GII: 1–0.5 mm, SS-GIII: 0.5–0.09 mm) and copper slag (CS-GI: 2–1 mm) as an alternative fine aggregate. Additionally, steel fibers are incorporated at dosages of 0.5 %, 1 %, and 2 % to assess their impact on extrudability and buildability. Following systematic printing trials, ten optimal mix compositions demonstrating superior buildability, shape stability, and extrusion efficiency are selected for in-depth analysis. The selected mixes undergo flowability assessments, extrudability evaluations, stress growth tests, compressive strength testing, and microstructural characterization to evaluate early-age properties. The experimental findings reveal that both static and dynamic yield stress increase over resting time, following the order CS-GI > SS-GI & GII > SS-GIII. Copper slag-based formulations exhibit enhanced rheological performance, which is attributed to improved particle packing density and reduced porosity. Moreover, both plain and fiber-reinforced copper slag mixes demonstrate superior compressive strength across the X, Y, and Z axes due to their vitreous microstructure and densified matrix. The anisotropic strength behavior is examined for copper slag replacements at 25 %, 50 %, 75 %, and 100 % substitution levels. Microstructural analyses indicate that early nucleation of calcium silicate hydrate (CSH) gel contributes to ultra-high-strength development. While steel fiber incorporation reduces flowability, it enhances rheological stability and printability through mechanical interlocking within the binder matrix. The research establishes copper slag as a viable alternative for sustainable applications for 3D concrete printing of UHPC.

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34 References

5 Citations

BibTeX

@article{ravi_prem_giri_bhas.2025.TDPo3PUwSSCSaF,
  author            = "Darssni Ravichandran and Prabhat Ranjan Prem and Greeshma Giridhar and Gollapalli S. Vijaya Bhaskara and Srinivasan Maheswaran",
  title             = "Time-Dependent Properties of 3D-Printed UHPC with Silica Sand, Copper Slag, and Fibers",
  doi               = "10.1016/j.istruc.2025.108819",
  year              = "2025",
  journal           = "Structures",
  volume            = "75",
  pages             = "108819",
}

Formatted Citation

IEEE

D. Ravichandran, P. R. Prem, G. Giridhar, G. S. V. Bhaskara and S. Maheswaran, “Time-Dependent Properties of 3D-Printed UHPC with Silica Sand, Copper Slag, and Fibers”, Structures, vol. 75, p. 108819, 2025, doi: 10.1016/j.istruc.2025.108819.

CMOS

Ravichandran, Darssni, Prabhat Ranjan Prem, Greeshma Giridhar, Gollapalli S. Vijaya Bhaskara, and Srinivasan Maheswaran. “Time-Dependent Properties of 3D-Printed UHPC with Silica Sand, Copper Slag, and Fibers”. Structures 75 (2025): 108819. https://doi.org/10.1016/j.istruc.2025.108819.